Automatic Document Feeder End Fence and Release Unit
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Solution Overview
Problem
In medium-sized and small-sized automatic document feeders, the constraints of limited space and the need for efficient document handling and maintenance lead to issues such as reduced accuracy in document alignment, difficulty in cleaning the reading surface, and challenges in maintaining proper nip pressure for paper ejection, due to the compact design and shared functions of the paper ejection and feeding rollers.
Innovation Solution
The design includes a feeding unit for reading one side of a document, a second image reading unit for the other side, a release unit that supports the reading guide and allows for its movement, and a paper ejection tray with a separate end fence configuration, where the rotational pivot of the release unit is positioned downstream, enabling space-saving and effective document handling and maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the distance from the second document reading unit to the paper ejection port is shortened to prevent documents from sticking out, then document containment is improved, but maintenance accessibility and cleaning ability deteriorate
Solution Approach 1:
The release unit is designed to be movable between a closed position (for normal operation) and an open position (for maintenance). This dynamic configuration allows the system to switch between document containment mode and maintenance accessibility mode, resolving the contradiction between these two requirements.
Solution Approach 2:
The paper ejection tray is divided into a fixed portion and a movable release unit portion. This segmentation allows the release unit to be independently moved for maintenance purposes while maintaining the compact overall structure for document containment during operation.
2Volume of moving object
If the ADF is designed with compact size for medium-sized and small-sized models, then machine size is reduced, but document alignment accuracy and nip pressure control deteriorate
Solution Approach 1:
The end fence is configured to be movable in the document width direction (lateral dimension) while maintaining compact design in the document length direction. This dimensional approach allows sufficient alignment accuracy in the critical feeding direction while keeping the overall machine footprint compact.
Solution Approach 2:
The end fence is designed to be movable rather than fixed, allowing it to be adjusted to accommodate different document sizes and types. This dynamic adjustment capability maintains alignment accuracy for various documents within the compact ADF structure.
3Ease of repair
If the release unit is positioned upstream for easy maintenance, then cleaning accessibility is improved, but document containment and prevention of falling off deteriorate
Solution Approach 1:
The release unit can be moved to an open position for maintenance access to the reading surface, then returned to a closed position that restores proper document containment. This dynamic positioning resolves the contradiction between maintenance accessibility and document containment.
Solution Approach 2:
The release unit acts as an intermediary element that can be temporarily moved for maintenance purposes without permanently compromising document containment. When closed, it restores the proper document path and containment geometry.
4Device complexity
If the paper ejection roller pair shares feeding function in compact design, then device complexity is reduced, but nip pressure control and document handling deteriorate
Solution Approach 1:
The paper ejection roller pair is designed to perform both feeding and ejection functions. This multi-functionality reduces the number of separate components needed in the compact ADF while maintaining reliable document handling through proper roller positioning and pressure control.
Solution Approach 2:
The roller pair is positioned and configured with specific local characteristics (nip pressure, rotation speed, surface texture) optimized for both feeding and ejection tasks, allowing a single component to reliably perform multiple functions that would otherwise require separate dedicated rollers.
Data Source
AI summary
An automatic document feeder comprises: a feeding unit that causes an image of a first side of a document to be read by a first image reading unit; a second image reading unit that reads an image of a second side of the document; a release unit that supports a reading guide opposite to a reading surface of the second image reading unit and enables underneath of the reading surface to be released; and a paper ejection tray on which the document having been subjected to image reading and ejected from a paper ejection roller pair is accumulated, wherein an end fence that rises up at a document ejection direction upstream side of the paper ejection tray is configured of separate members that are an upper portion and a lower portion, and a rotational pivot of the release unit is provided downstream from the end fence in a feeding direction.